Arrays of male touch fastener elements, e.g., loop-engageable hooks, may be provided on a surface of a flexible sheet-form substrate, such as by passing the substrate through a molding nip with moldable resin, and forcing the resin into miniature cavities to form complete fastener elements, or fastener element preforms, extending from a layer of resin laminated to the substrate surface. It has been more recently taught that such methods can be performed so as to provide fastener elements on only limited regions of the substrate surface, such as spaced-apart longitudinal lanes or islands, leaving other surface regions free of the resin and exposed. Improvements in the methods of making such products, and in processing longitudinally continuous flexible substrates in general, are sought.